Speaker Design

1.2

1.2 Materials causing environmental concern are identified in relation to the task.MDF releases an odor which can irritate the eyes and nose. These compounds include aldehydes, terpenes and methanol. MDF also contains Formaldehyde. Formaldehyde is classified as a human carcinogen and has been linked to nasal and lung cancer, with possible links to brain cancer and leukaemia. Short-term exposure to formaldehyde can be fatal. Long-term exposure to low levels of formaldehyde may cause respiratory difficulty, eczema, and sensitization.MDF produces very fine dust during processing and the dust particles act as a carrier of absorbed formaldehyde to the lower airways of lungs. Wood dust and formaldehyde together have been reported to cause respiratory irritation with symptoms of dryness of throat, rhinitis and eye irritation as well as occupational skin disease. To avoid harm from the MDF keep the workshop well ventilated. When MDF is burned it can release emissions that can be harmful to the environment. The best way to reduce emissions is to carefully control combustion temperature - keep it below 800°C - and avoid using fuel with chlorine in it. Foam carpet underlay is highly flammable. It has a high fire growth rate and is also very sensitive to ignition. This could produce a problem if the speakers become overheated or the underlay is near to something hot in the workshop.

1.1

1.1 Environmental hazards are identified in relation to the task.MDF is full of Formaldehyde which can be harmful to humans and the environment. It can cause headaches, watery eyes and eventually cancer. MDF also releases other toxins into the environment. In some countries, such as Australia, wood from native forests is used to make the chips that go into MDF. This is a danger to the environment as native forests are becoming rarer and rarer. Luckily a lot of MDF manufacturers are beginning to use recycled materials, such as straw and bamboo, as sustainable alternatives to native wood.

STANDING WAVE/PHASE CANCELLATION NOTES

Standing waves are wave forms that 'stand' on the edge of the front plate, lingering around not dispersing properly. As they linger they interfere with other waveforms coming through, cancelling out waves that you want to reproduce. It produces a baseless speaker response.This is easily fixed by rounding the edges of the front plate. The standing waves will disperse outwards as they hit the edge, stopping any wave cancellation.

CARPET UNDERLAY NOTES

Carpet underlay is an absorber of unwanted frequencies inside the box. Low frequencies inside the box bounce of the wall of the box, hitting other frequencies that need to be reproduced, cancelling out the bass. The speakers sound tinny. The carpet underlay absorbs any unwanted frequencies.

BRACING NOTES

Bracing is an acoustic treatment of the box. It allows the box to stop the flexing waves forms that are reproduced inside it. The port is the 'interface' between the box and the outside. It counterbalances the moving of the voice coil by pushing out when the coil is moving in (through magnetism) and vice versa.

TOOLS LIST

TOOLS LIST
Hand Drill
Drill Press
Palm Sander
Belt Sander
Circle Cutter
Soldering Iron
RaspScissors
MalletWire
StripperCutters
PliersDrill pieces
Soldering Iron